Ultra-Low Cryoablation for Scar-Related VT Ablation: Results From the US Early Feasibility Study

BACKGROUND: A limitation of ablation for scar-related ventricular tachycardia (VT) is insufficient lesion depth to address nonendocardial substrate. Ultra-low temperature cryoablation (ULTC) at -196°C has been shown to create transmural lesions in preclinical models. Early human studies in Europe have shown safety and efficacy. METHODS: An EFS (Early Feasibility Study) was designed in collaboration with the Food and Drug Administration as a prospective, nonrandomized evaluation of the acute safety and effectiveness of ULTC ablation for scar-related VT. RESULTS: Twenty patients (age 63±14 years; 5% women; LVEF 36±13%; 45% ischemic and 55% nonischemic) underwent VT ablation with ULTC from September to December 2023 at 4 clinical sites. Ablation strategies included substrate modification during sinus rhythm, as well as activation and entrainment mapping when hemodynamics permitted. Mean ULTC lesions were 9.9±3.6, with a total freeze duration of 47±22 minutes. Noninducibility of the targeted VTs was observed in 13 of 14 patients with inducibility tested both pre- and postablation. There were no procedural strokes, tamponades, or deaths. One suspected cardiac perforation without tamponade was conservatively managed. One patient was excluded from the follow-up efficacy analysis due to RF use, and another lacked postacute follow-up due to death from heart failure 1 month post-procedure. Among surviving per-protocol patients, 23.7±4.3 weeks of freedom from VT and implantable cardioverter defibrillator shock were 61.1% (11/18) and 83.3% (15/18), respectively. CONCLUSIONS: In a US EFS, ULTC therapy was safe and effective for the treatment of scar-related VT. The EFS design, in collaboration with the Food and Drug Administration, represents an important initiative to accelerate the evaluation of new medical technologies in the United States. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05675865.